A large form factor optical transceiver, e.g. an X2 optical transceiver generally indicated at 1 in FIGS. 1a and 1b, includes an optical coupler 2 at a front end thereof, with optical bores 3 and 4 for receiving a conventional SC optical duplex connector (not shown), which has a distance between the center lines of the active optical bores of approximately 12.7 mm. A transmitter optical sub-assembly (TOSA) and a receiver optical sub-assembly (ROSA) are mounted within a housing 6, which includes a base 7 and a cover 8. The housing 6 is approximately 36 mm wide, 23 mm high and 91 mm long, with heat sink fins 9 extending upwardly from the cover 8 for dissipated heat generated therein. A module printed circuit board (PCB) including control and monitoring circuitry for the ROSA and TOSA has a seventy-pin electrical connector 11 extending therefrom and from a rear end of the housing 6 for interconnection with a mating host electrical connector 12 mounted on a printed circuit board (PCB) 13 of a host device 14. The host device 14 includes a bezel with openings therein, which are sized to receive the housing 6 and abut an abutting flange 17 extending from around the optical connector 2. A guide rail 18 is mounted on the host PCB 13 for guiding the housing 6 until the electrical connector 11 engages the host electrical connector 12, the abutting flange 17 abuts the bezel, and a resilient latching element 19 extends into a corresponding latching recess in the guide rail 18. The X2 multi-source agreement (MSA) as found at X2MSA.org is incorporated herein by reference. Other large form factor transceivers include the XPAK transceiver and the XENPACK transceiver, the MSA's of which, found at xpak.org and xenpack.org, respectively, are incorporated herein by reference.
Conventional small form factor (SFF) transceivers, generally indicated at 20 in FIG. 2, include a ROSA 21 mounted in a housing 22 along side a TOSA 23. A PCB 24 includes TOSA and ROSA control and monitoring circuitry, e.g. chip 25. The housing 22 is approximately 8.6 mm high, 13.7 mm wide and 49 mm long. An electrical connector 27 extends from a rear end of the housing 22 for mating with a host mounted electrical connector (not shown). For a board mounted SFF transceiver the electrical connector includes pins extending from the PCB 24; however, for a pluggable SFF transceiver (SFP) the electrical connector 27 includes a card edge connector formed in the end of the PCB 24. Bores 33 and 34 form an optical connector on a front end of the housing 22 for receiving an LC duplex optical connector 35 with a distance between optical bore centerlines of 6.35 mm or half that of an SC duplex optical connector. Typically an SFP transceiver is mounted in a small metal cage fixed to the host circuit board, with an electrical connector at one end thereof for receiving the electrical connector 27.
With the popularity of the original large form factor transceivers, the supply chain for transceivers is heavily populated with housings, heat sinks, electrical connectors and guide rails useful only for large form factor devices. With the latest trend towards increasing transceiver density, small form factor devices have become more popular, while the large form factor devices and all the components therefor have become obsolete.
An object of the present invention is to overcome the shortcomings of the prior art by providing a large form factor transceiver housing suitable for receiving a plurality of small form factor transceivers enabling large form factor components to be used with small form factor transceivers.